Stoker



Nov. 8, 1938. e. A. STEPHENS 2,135,632

STOKER Filed July 2, 1936 2 Sheets-Sheet 1 Nov. 8, 1938. G. A. STEPHENS 9 5 I STOKER I Filed July 2, 1956 2 Sheets-Sheet 2 Patented Nov. 8, 1938 Gordon A. Stephens, Long Branch, Ontario, Canada, assignor to American Engineering Company, Philadelphia, Pa., a corporation of Pennsylvania Application July 2, 1936, Serial No. 88,545 10 Claims. (01. 122-4) locks l? to protect them against the action of the fuel and ash, if it is so desired.

The stoker 3 in the present instance comprises an underfeed section 18 consisting of alternately disposed retorts I9 and tuyere rows 29, and an overfeed extension grate section 2i. Fuel is supplied to the stoker from hoppers 22 mounted This invention relates to stokers, and more particularly to fluid cooled stokers of the multiple;

retort underf-eed type.

One object of the present invention is to provide a simplified and generally improved stoker of the stated character.

Another object is to provide an improved fluid cooling system for stokers which insures proper circulation of the fluid therethrough under all conditions of operation with the use of a minimum of fluid connections with the source of fluid supply.

A further object is to provide a simplified and compactly arranged furnace comprising a continuous discharge stoker arranged adjacent the boiler and including a novel fluid system disposed in cooling relation with the stoker and the walls of the furnace.

Other and further objects of the invention will become apparent as the description of themvention progresses.

Of the drawings:

Fig. 1 is a longitudinal sectional view take through one of the stoker retorts showing the arrangement of the boiler and the stoker of the furnace, andthe improved fluid cooling system associated therewith.

Fig. 2 is a plan view partly in section taken substantially along line 2-2 of Fig. 1, and

Fig. 3 is a plan view of the fluid cooling system for the stoker.

Referring to the drawings, the numeral I designates generally a furnace comprising a boiler 2 fired by a multiple retort underfeed stoker 3. The boiler 2 in the present instance is of the vertical tube type and consists of a steam drum 4, a mud drum 5, and a series of substantially vertical banks of tubes 6 extending between said drums. The combustion chamber 1 of the furnace is bounded at the sides thereof by walls 8 and 9, at the front by a wall ill, at the top by an upwardly and rearwardly inclined wall I I, and at the rear by the forwardly disposed bank of boiler tubes H2. The walls 8, 9, Ill and II may be constructed of any suitable refractory material.

The side walls 8 and 9 have each provided therein adjacent stoker 3, a series of inclined tubes l3 and M respectively. Tubes l3 and I4 are connected at the upper ends thereof to headers l5 and I6 respectively, disposed outwardly of front wall it, and at their lower ends to mud drum 5.

Tubes 13 and I4, and the lower por-' tions of tubes l2 may be covered by protective,

exteriorly of the front wall which empty into cylinders '23 in line with the retorts, and rams (not shown) operating in said cylinders feed predetermined quantities of fuel to said retorts upon each reciprocation thereof. Fuel is under fed along the retorts [9 by a series of pushers 24. The rams and pushers are operated by any suitable p'ower mechanism 25, the pushers being connected thereto by a link and lever mechanism indicated at 26.

The lower end of each retort has provided therein a horizontally disposed dead plate 21, which lies in substantially the same plane as the overfeed section 2!.

Extending rearwardly from a header 28 disposed transversely beneath the stoker are a series of fluid conducting tubes 29.

These tubes are mounted inintimate relation with dead plates 2'! and terminate'in a second transversely disposed header 3!].

As shown more particularly in Figs. 2 and 3, each dead plate 21 has two tubes associated therewith, although it is apparent that the number of tubes so disposed may be varied without departure from the invention. Disposed between each pair of tubes 29 and'ex tending forwardly from header 3% is a second pair of tubes 33.

These tubes extend in parallel relation with tubes 29 between header 3% and the lower end of tuyere rows 23. Tubes 3! then incline upwardly and forwardly and make intimate contact with said tuyeres, and then are bent upwardly so as to lie in abutting relation with wails it and H and terminate at their 8 and ii.

Header 28 is connected to drum 5 of the boiler by a pair of downtake connections 3-3 and 35, while headers l5 and [6 are connected to steam drum 4 by risers 36 and 3'1, respectively. As shown in Figs. 1 and 2, risers 3B and 31 extend through front wall It] and lie in abutting relation with top wall I and thus also serve to cool a portion of said wall.

It therefore is seen that fluid from boiler 2 flows into header 28 through downtake connections 34 and 35, thence through tubes 29 to header 30, and thence through tubes 3| to steam drum 4, as indicated by the arrows in Fig. 3. By this construction it is unnecessary to provide additional connections between header 3|] and the boiler 2.

Mounted on a rod 38, supported in bearings 38, attached at intervals to header 30, are a series of dump plates 39. A lever 40 secured to one end of rod 38 and disposed exteriorly of wall 8 is provided to adjust plates 39 to vary the size of the discharge opening 4| defined by said plates, the bank of tubes 12, and the rear wall 42 of an ash pocket 43, as shown in Fig. 1.

Draft air is supplied to the stoker by any suitable fan mechanism (not shown) and enters a plenum chamber 44 disposed beneath the stoker through a duct 45. This air passes between the grates of the stoker and flows through the combustion chamber 1 and the various boiler passes, as indicated by the arrows in Fig. l, and discharges to the stack through an opening 46 provided in the rear wall 41 of the furnace.

The overfeed grate section 2| in the present instance consistsof a series of metallic or refractory blocks 48 secured to the rearwardly disposed portions of tubes 29 and 3|, and the top surface of header 30. A slight space is provided between the adjacent edges of these blocks through which draft air may pass to the fuel bed, overlying the same. Other forms of grate blocks may also be employed if it is so desired without departing from the invention. Draft air is supplied to extension grate 2| fr'om plenum chamber 44 through the connecting passage 49. Dampers 50 may be provided in this passage to control the flow of air to the overfeed extension section 2|, if it is so desired. Any siftings passing between blocks 48 of the extension grate section gravitate into a hopper 5| disposed therebeneath. These siftings may be removed from the hopper from time to time by simply opening a closure 52 provided at the bottom thereof.

From the foregoing description it is seen that a simplified and highly improved stoker has been provided. The grates, the dead plates and the overfeed grate section of the stoker, as well as the walls of the furnace, are effectively cooled by a simplified, as well as highly eflicient cooling system. Also, by arranging the boiler and stoker in the manner shown herein intermediate walls may be dispensed with. The arrangement of the dump plates in respect to the forwardly disposed bank of boiler tubes further provides a continuous ash discharge construction wherein the rate of ash discharge may be varied to best suit the operating conditions of the furnace.

While the embodiment herein shown and described is admirably adapted to fulfill the objects primarily stated, it is to be understood that the invention is not to be limited thereto, since .it may be embodied in other forms, all coming within the scope of the claims which follow.

What is claimed is:

1. In a furnace, the combinationof a stoker, comprising alternately disposed retorts and tuyere rows, substantially horizontally disposed fuel supporting means provided at the lower end of each of said retorts, means comprising one or more fluid conducting tubes disposed longitudinally of and in cooling relation with said fuel supporting means, headers connecting the opposite ends of said tubes, a boiler, means connect- Tf ing one of said headers with said boiler, means comprising one or more tubes extending from the other of said headers and disposed in cooling relation with said tuyere rows, said last mentioned tubes being connected to said boiler whereby fluid from said boiler circulates to said first mentioned header and through said first mentioned tubes to said second header, thence through said second mentioned tubes and back to .the boiler. 2. In a furnace, the combination of a stoker,

comprising alternately disposed retorts and tuyere rows, a dead plate disposed at the lower end of each of said retorts and extending between adjacent tuyere rows, one or more fluid conducting tubes disposed longitudinally of and in cooling relation with each of said dead plates, front and rear headers connected to said tubes, a boiler, means connecting said front header to said boiler, one or more fluid conducting tubes extending from said rear header and disposed in cooling relation with each of said tuyere rows, a combustion chamber disposed above said stoker having front, side and top walls, said last mentioned tubes extending upwardly and lying in substantially abutting relation with said front and top walls and terminating in said boiler.

3. In a furnace, the combination of a stoker, comprising alternately disposed retorts and tuyere rows, a dead plate disposed at the lower end of each of said retorts, one or more fluid conducting tubes mounted in cooling relation with each of said dead plates, front and rear headers connected to said tubes, a boiler, means connecting said front header to said boiler, one or more fluid conducting tubes extending from said rear header and. disposed in cooling relation with each of said tuyere rows, a combustion chamber disposed above said stoker having front, side and top walls, said last mentioned tubes extending upwardly and lying in substantially abutting relation with said front and top walls and terminating in said boiler, means comprising a series of fluid conducting tubes disposed adjacent each of said side walls, a header connected to one end of each of said series of tubes, the other end of said tubes being connected to said boiler, and risers connecting said headers with said boiler, said risers lying in substantially abutting relation with said top wall.

4. In a furnace, the combination of a stoker having an underfeed section and an overfeed section, said underfeed section consisting of alternately'disposed retorts and tuyere rows, fuel supporting means disposed at the lower ends of said retorts and extending between adjacent tuyere rows, said fuel supporting means being disposed in substantial alignment with said overfeed section, fluid conducting means mounted in cooling relation with said fuel supporting means, overfeed section, and tuyere rows, and means for supplying fluid to said fluid conducting means.

5. In a furnace, the combination of a stoker having an underfeed section and an overfeed section, said underfeed section consisting of alternately disposed retorts and tuyere rows, dead plates disposed at the lower ends of said retorts and in substantial alignment with said overfeed section, fluid conducting means mounted in cooling relation with said dead plates, overfeed 'section, and tuyere rows, and means for supplying fluid to said fluid conducting means.

6. In a furnace, the combination of a stoker having an underfeed section and an overfeed section, said underfeed section consisting of alternately disposed retorts and tuyre rows, fuel supporting means disposed at the lower ends of said retorts and extending between adjacent tuyere rows, said fuel supporting means being disposed in substantial alignment with said overfeed section, one or more fluid conducting tubes mounted in cooling relation with said fuel supporting means and portions of said overfeed section, front and rear headers connected to the opposite ends of said tubes, one or'more fluid conducting tubes extending forwardly of said rear header and in cooling relation with other portions of said overfeed section, and means for supplying fluid to said front header.

7. In a furnace, the combination of a stoker having an underfeed section and an overfeed section, said underfeed section consisting of alternately disposed retorts and tuyre rows, fuel supporting means disposed at the lower ends of said retorts and extending between adjacent tuyere rows, said fuel supporting means being disposed in substantial alignment with said overfeed section, one or more fluid conducting tubes mounted in cooling relation with said fuel supporting means and portions of said overfeed section, front and rear headers connected to the opposite ends of said tubes, one or more fluid conducting tubes extending forwardly of said rear header, a portion of each of said last mentioned tubes lying in substantially the same plane as said first mentioned tubes and in cooling relation with other portions of said overfeed section, and a portion of said last mentioned tubes lying in cooling relation with said tuyere rows, and means for circulating a cooling medium through said tubes and headers.

8. In a furnace, the combination of a stoker having an underfeed section, and an extension grate section, said underfeed section consisting of alternately disposed retorts and tuyre rows, fuel supporting means disposed at the lower end of each of said retorts and extending between adjacent tuyere rows, said fuel supporting means being disposed in substantial alignment with said extension grate section, fluid conducting means mounted in cooling relation with said fuel supporting means, extension grate section, and tuyre rows, and means for supplying fluid to said fluid conducting means.

9. In a furnace, the combination of a stoker having an underfeed section, and an extension grate section, said underfeed section consisting of alternately disposed retorts and tuyre rows, fuel supporting means disposed at the lower ends of said retorts and extending between adjacent tuyere rows, said fuel supporting means being disposed in substantial alignment with said extension grate section, one or more fluid conducting tubes mounted in cooling relation with said fuel supporting means and portions of said extension grate section, front and rear headers connected to the opposite ends of said tubes, one or more fluid conducting tubes extending forwardly of said rear header, a portion of each of said last mentioned tubes lying in substantially the same plane as said first mentioned tubes and in cooling relation with other portions of said extension grate section, and a portion of said last mentioned tubes lying in cooling relation with said tuyere rows, and means for circulating a cdoling medium through said tubes and headers.

10. In a furnace, the combination with a boiler having a plurality of banks of substantially vertical tubes, of a stoker comprising an underfeed section and an overfeed section for firing said boiler, said underfeed section consisting of alternately disposed retorts and tuyre rows, a dead plate disposed at the lower end of each of said retorts and lying in substantially the same plane as said overfeed section, means for feeding fuel to and along said stoker, means comprising a series of fluid conducting tubes mounted in cooling relation with said dead plates, overfeed section, and tuyere rows, means connecting said tubes to said boiler, adjustable dump plates disposed at one end of said stoker for supporting the residue fed from the latter, said dump plates being spaced from one of the banks of tubes of said boiler forming a discharge opening for said residue, and means for adjusting said plates to vary the size of said discharge opening.

GORDON A. STEPHENS. 

